The present invention relates to a printer and, more particularly, to a recording member pressing device in a printer which automatically selects a suitable pressing position of each of paper pressing rollers according to the size of a recording member inserted.
FIG. 1 shows a perspective view of a conventional paper pressing system for a recording paper feed device in a printer. A platen 40 is rotated around an axis 41 (as indicated by a chain line) connected with a rotating mechanism. Under the platen 40, a plurality of paper feed rollers 43 are rotatably provided around an axis 42 (as indicated by a chain line) parallel with the axis 41 of the platen 40 and are in contact with a part of the circumference surface of the platen 40. A plurality of paper pressing rollers 45 positioned above the platen 40 are rotatably provided around an axis 44 (as indicated by a chain line) parallel with the axis 41 of the platen 40 and are slidably moved along the axis 44. The paper pressing rollers 45 can be detached from the surface of the platen 40 by operating a manual lever. Usually, the paper pressing rollers 45 press a recording paper around the platen 40 because the axis 44 of the paper pressing rollers 45 is stressed by a spring.
When the recording paper is inserted from the rear side and the upper side of the platen 40 and the platen 40 is rotated, the recording paper is forwarded to the under portion of the platen 40 along the platen 40 and is passed between the platen 40 and the paper feed rollers 43, and after that, the recording paper is guided to the front side and the upper side of the platen 40 to apply the recording paper to a printing position of the printer.
When the recording paper is reached at the printing position, the paper pressing rollers 45 press the recording paper on the platen 40. In this case, the pressing position in the vertical direction of each of the paper pressing rollers 45 is manually selected so that the paper pressing rollers 45 do not badly influence a printing operation of the printer.
In the printer having the above recording paper pressing system for a paper feed device, in case where different size recording papers are used in it for printing, the pressing position of each of the paper pressing rollers 45 must be manually changed by the operator every time the size of the recording paper is changed. The pressing positions of the paper pressing rollers 45 must be set on the right and the left sides of the recording paper outside a printing area of the recording paper. The manual operation may cause the missetting of or the nonselection of the pressing position of each of the pressing rollers when the different size recording papers are applied to the printer.
In particular, in an ink jet type printer in which ink droplets are jetted from a nozzle of a printing head on the printing position of the recording paper, if any paper pressing roller is set out of the recording paper, the size of the printed characters may be varied according to the recording paper condition. On the other hand, when some of the paper pressing rollers press the printing area of the recording paper, an ink jetted on the printed paper may be scattered by the rollers because the ink is not perfectly dried. Therefore, the printing quality may be remarkably reduced.
Recently, an automatic paper supply device has been used in the printer. However, if the different size recording papers are applied by the automatic paper supply device, the capability of the automatic paper supply device is remarkably decreased because the pressing positions of the paper pressing rollers of the paper pressing device must be manually selected by the operator.